"""合并(将两个有序的列表合并成一个有序的列表)"""
items = []
index1, index2 = 0, 0
while index1 < len(items1) and index2 < len(items2):
    if comp(items1[index1], items2[index2]):
        items.append(items1[index1])
        index1 += 1
    else:
        items.append(items2[index2])
        index2 += 1
items += items1[index1:]
items += items2[index2:]
    return items